Tripod leg



May 25, 1948. T. c. FURNAS, JR

TRIPOD LEG Filed Sept. 9. 1946 2 Sheets-Sheet 1 may;

May 25, 1948. T. c. FURNAS, JR'

TRIPOD LEG Filed Sept. 9, 1946 2 Sheets-Sheet 2 Patented May 25, 1948 UN IT ED STATES;

@FFKE TRIPOD LEG Thomas C. Furnas, J12, Cambridge, Application September 9, 1946, Serial No. 695,775

5 Claims. (Cl. 248-473) This invention relates to tripods and more particularly to extensible tripods for supporting cameras, transits, plotting boards, and the like.

Among the several objects of the invention may be noted the provision of a rugged, light-weight, rigid tripod, having a large limit of extension and which when collapsed is of convenient size to carry; the provisionof an extensible tripod of the class described which is constructed primarily of standard extruded or rolled metal shapes readily obtainable on the market; and the provision of a tripod of this class which is economical to manufacture. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,

Fig. 1 is a side elevation of the tripod standing ready for use but unextended;

Fig. 2 is an enlarged partial plan View of Fig. 1;

Fig. 3 is a cross section taken on line 3-3 of Figs. 1 and 6;

Fig. 4 is a side elevation of a leg hinge and associated parts;

Fig. 5 is a horizontal section taken on line 5--5 of Fig. 4;

Fig. 6 is a detail (partly in section) of a leg clamping device;

Fig. '7 is a view similar to Fig. 4 but viewed from the opposite side;

Fig. 8 is an isometric view of a hinge piece; and,

Fig. 9 is an isometric view of another hinge piece.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Many tripods now in use by photographers, surveyors, and others are constructed of wood, insofar as are concerned the telescoping legs. This wood must be of bestquality as to grade and seasoning. Even then they tend to warp and stick. Frequently the clamping devices for positioning the legs of wood in tripods are built in such a manner that after continued use the legs become dented and scarred by the clamp which so distorts the shape of'thezleg that it will not slide freely within its telescoping member. To produce a telescoping tripodof wood requires skill are located on a common axis. legs 8 with the hinge pieces 53 are fastened 'to-.

and careful workmanship so that its parts will easily slide within one another.

Metal tripods available in the past have been unsatisfactory because of the use of thin metal sections (in order to reduce the weight) which resulted in limber structures subject to vibration.

By means of the present invention I have overcome these objectionable features of the wooden and metal tripods obtainable hereto-fore.

Referring now more particularly to Fig. 1, the new tripod consists of three expansible legs l each of which is like the other. These are hinged to a base plate 2'; at their upper ends. At the lower end of each of the legs l a rubber or other friction-producing foot 5.

The legs 3 are spaced asout the base plate '3 120 from each other.

The legs l are constructed primarily of two aluminum angles {3 between which is 'slidably mounted a 'i'-shaped aluminum piece ii. These shapes are those readily obtainable in finished form. The material to he used not necessarily confined to aluminum, and may be, for example, magnesium Duralumin, or the like, all of which are available in standard angle and Tshap'es and sizes, and may be obtained without need of further finishing. As shown in the drawing, each angle fits into the angle between the web and part of the head of the T.

Referring to Figs. 4i, 5, 7, 8 and 9 each of the angles 55 for one leg has screwed or otherwise secured at the upper end an angled hinge butt ['3. This hinge butt fits into the angle 9 snugly and is fabricated from heavier stock than the angle 9. One wall of the angle is is cut away to form a space if: between it and one web of theangle 9 '(seeFigs. '7 and. 9). The extension ll formed by the cut-away portion of '53 is provided with a hole iii. A similar hole 2i is also provided in the adjacent wall of the angle s. These two holes The two identical gether by a third center hinge-butt piece 23. This third'hinge-butt piece is also of a somewhat greater thickness than the -material of the legs (see Fig. 8).

One leg 25 of this piece 23 has a hole 2? similar in size to holes l9 and El and coaxial therewith. Each other arm 29 of the piece 23 is fastened by screws or the like 3! to one wall of the angles 9, with the holes 59, El and 2? aligns The leg 25 of the piece 23 is positioned between the other walls of the angles 9 and forms a space 33 between the angles (see'Fig; '7). This leg, 25 functions as a spacer for the angles 9. The spacingis controlled by the thickness of the part 25. Additional fastening means such as screws 35 are employed at right angles to the screws 3| inorder to form a rigid composite hinge-butt for the upper ends of the legs I.

The resulting five hinge extension portions, constituted by members I1, both upper ends of angles 9, and the spacer 25 are interleaved with four hinge butts III of a base hinge piece 43. Three of-these base hinge pieces 43 are located 120 apart on the under side of the base plate 3, and are fastened by screws or the like 45. The depending butts M are provided with aligned holes 41 and are spaced from each other so as slidably to accommodate the hinge butts of the legs I before mentioned.

A hinge pin 49 in each of the three hinges is provided with extending threaded portions at each side to receive tightening wing-nuts 5I.

When the legs I are spread as shown in Fig. 1 the wing nuts 5i may be tightened to hold the tripod legs in this position; or they may be loosened to permit telescoping 0f the legs I for carrying purposes.

The base plate 3 may be hexagonal in plan or any other desired shape and is provided with holes 53 for mounting an instrument to be supported (not shown).

At the lower extremity, the angle 9 of each leg I is held by a channel piece 55 having awcover plate 51 secured to it by screws 59 (see Figs. 1, 3 and 6). These two parts 55 and 57 enclose the two angles 9 and the intermediate T-shaped piece II. The channel portion SI of the piece 55 has space between its sides to receive the walls of the two'angles 9 and the leg of the T-shaped piece II so that the web 53 of the T may slide therethrough.

L-shaped elongate members 9 and nesting holding means for the ends of these members 9. Likewise, the L-shaped end members I3 are nested into the opposite L-shapes of the members 9 (Fig. 9). Common fasteners hold the assembly together as shown in Fig. '7, with the coaxial openings I9, 2I and 21 all aligned to receive the pivot pins 49. This provides a convenient hinge and spacer construction.

It will be seen from the above that the inven: tion includes the provision of an extensible leg for a tripod or the like which is made up of simple, standard spaced L-shaped elongate members between which is a slidable, standard T-shaped elongate member. Also, the clutch mechanism which is shown in Figs. 3 and 6 is confined within the guide portions attached to the spaced L- shaped members through which slides the confined T-shaped member. This clutch mechanism is not only highly effective, but the internal parts of the clutch mechanism are well guarded.

Furthermore, the pivoted fiat jaw or clutch por- The cover plate 51 is channeled as at B5 to accommodate the passage of the flange portions 5! of the T-shaped member I I.

'A recess 69 is thus provided above and at each side of the channels Iii and in one recess 69 on each leg is pivoted a friction member I I. A portion of the wall of the one angle 9 is cut away as at I3 so that the friction member II bears directly against the web 63 of the movable T mem ber II. The surface of the friction member H is likewise cut to fit into the removed portion of the angle 9 and has a portion I5 extending adjacent the wall of angle 9 to a pivot pin FL This pivot pin confines the friction member 1| within the channel so that it will not be displaced. The pin extends from the channel 55 through the member II and into a wall of the angle 9 (see Fig. 3). A threaded wing screw 19 extends through the wall of each channel piece 55 and bears against the friction member II opposite the cutaway portion of angle 9. When the wing screw I9 is screwed through the member 55 it presses against the friction member II thereby forcing it against the web 63, thereby binding the latter.

At the upper ends of the members I!, guide blocksBI are screwed to the edges of the webs 63. These overlap the adjacent edges of the angles 9. Thus the members II are slidably confined between the walls of the angles 9, that is, in the space 33.

The members I I can be extended from the legs I almost the total length of the members or until the guide blocks 8| abut the channel pieces 55. Thus the total extension of the legs I is almost double that of the collapsed condition.

Each T-shaped end member 23 of Fig. 8 forms both aspacing member between the endsof the tion 1! is highly effective as a clutch, without de-. forming the web of the 'iT-shaped member where the latter is gripped.

From the above it will be clear that the web of each T-shaped member is indicated at 63, and its flanges are indicated at 5'l. Each angle member 9 has a web sliding on web 53 and a web sliding on a flange portion 5?.

In view of the above,'it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions'without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. An extensible leg for tripods and the like comprising'an elongate member of T-shape cross section having a central web and lateral flanges spaced elongate members having L shaped cross sections which arenested on opposite sides atthe first-named member, a part on at least one portion of the web of the T-shaped member confining it between said L-shaped members, surrounding means at the other end of said L-shaped members and spacedly joining them while surrounding and guiding the T-shaped member, a clutch lever pivoted between the surrounding means and one of said L-shaped members and engageable with the web of the T-shaped member, and a screw in the surrounding means and engageable with said clutch lever.

2. An extensible, leg for tripods and the like comprising an elongate member of T-shapecr0ss section having a central web and lateral flanges, spaced elongate members having L-shaped cross sections which are nested on'opposite sides of the first-named-member, the adjacent edges of two spaced webs of the L-shaped members and the edge of the web of the T-shaped member being substantially flush, a head part on at least one portion of the web of the T-shaped member confining it at one end between said L-shaped members, and means confining said L-shaped and T-shaped members at the other end of said L- shaped members.

3. An extensible leg for tripods and the like comprising a pair of elongate L-shaped members havingadjacent webs, hinge butt means at one end of said members and determining the spacing betweensaid webs, guide means atthe other end of said L-shaped members arranged also to determine said spacing, a second elongate member of T-section having a web slidable between said spaced webs of the L-shaped members, said second. member being slidable through said guide means, a pivoted clutch member confined within said guide means, an adjusting screw threaded through saidguide means and engageable and disengageable with said pivoted clutch member, said clutch member being engageable and disengageable with the web of said T-shaped member.

4. An extensible leg for tripods and the like comprising elongate members of L-shaped cross sections, a hinged butt at the upper ends of said members also forming a spacer, a clutch holder at the other end of said members and acting also as a spacer for said L-shaped members, a second elongate member of T-shaped section having its web slidable between webs of the L-shaped members, means attached at one end of said T-shaped member and slidably confining it between said L -shaped members, said T-shaped member passing through the clutch holder at the other end of the L-shaped members, one of said L-shaped members within the clutch holders being recessed to expose a portion of the web of the T- shaped member, a pivoted clutch jaw adjacent the recess and located within said clutch holder, and means threaded through said clutch holder and operable from the exterior of the clutch holder and cooperating with said clutch 5. In a leg for tripods and the like comprising two adjacent elongate L-shaped members, a hinge-butt and spacer comprising a T-shaped part, said T-shaped part having a portion functioning as a spacer between the elongate L- shaped members, the ends of said elongate L- shaped members being nested in opposite angles of said T-shaped part, L-shaped hinge-butt parts nested in opposite angles of said L-shaped members, fasteners for holding said members rigidly assembled, and coaxial openings passing through the end portions of the four L-shaped members and the spacing portion of the T-shaped member.

THOMAS C. FURNAS, JR.

REFERENCES CITED FOREIGN PATENTS Country Date France Sept. 3, 1932 Number 

